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Title: Epitaxial stabilization and structural properties of REMnO{sub 3} (RE = Dy, Gd, Sm) compounds in a layered, hexagonal ABO{sub 3} structure.

Abstract

No abstract prepared.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC); National Science Foundation (NSF)
OSTI Identifier:
920977
Report Number(s):
ANL/MSD/JA-59704
Journal ID: ISSN 0003-6951; APPLAB; TRN: US200805%%3
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Appl. Phys. Lett.; Journal Volume: 91; Journal Issue: 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; EPITAXY; DYSPROSIUM OXIDES; GADOLINIUM OXIDES; SAMARIUM OXIDES; MANGANESE OXIDES; MORPHOLOGY; HEXAGONAL LATTICES

Citation Formats

Balasubramaniam, K. R., Havelia, S., Salvador, P. A., Zheng, H., Mitchell, J. F., Materials Science Division, and Carnegie Mellon Univ. Epitaxial stabilization and structural properties of REMnO{sub 3} (RE = Dy, Gd, Sm) compounds in a layered, hexagonal ABO{sub 3} structure.. United States: N. p., 2007. Web. doi:10.1063/1.2819606.
Balasubramaniam, K. R., Havelia, S., Salvador, P. A., Zheng, H., Mitchell, J. F., Materials Science Division, & Carnegie Mellon Univ. Epitaxial stabilization and structural properties of REMnO{sub 3} (RE = Dy, Gd, Sm) compounds in a layered, hexagonal ABO{sub 3} structure.. United States. doi:10.1063/1.2819606.
Balasubramaniam, K. R., Havelia, S., Salvador, P. A., Zheng, H., Mitchell, J. F., Materials Science Division, and Carnegie Mellon Univ. Mon . "Epitaxial stabilization and structural properties of REMnO{sub 3} (RE = Dy, Gd, Sm) compounds in a layered, hexagonal ABO{sub 3} structure.". United States. doi:10.1063/1.2819606.
@article{osti_920977,
title = {Epitaxial stabilization and structural properties of REMnO{sub 3} (RE = Dy, Gd, Sm) compounds in a layered, hexagonal ABO{sub 3} structure.},
author = {Balasubramaniam, K. R. and Havelia, S. and Salvador, P. A. and Zheng, H. and Mitchell, J. F. and Materials Science Division and Carnegie Mellon Univ.},
abstractNote = {No abstract prepared.},
doi = {10.1063/1.2819606},
journal = {Appl. Phys. Lett.},
number = 2007,
volume = 91,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Thin films of RE{sub 2}Ti{sub 2}O{sub 7} (RE=La, Nd, Sm, Gd) were deposited on single crystal SrTiO{sub 3} (110) substrates at 900 deg. C using pulsed laser deposition. X-ray diffraction (XRD) results showed sharp (00k) peaks (in theta-2theta scans) with narrow rocking curves (omega-scan peak widths of 0.4-0.9{sup o}), indicating that all compositions adopted the (110)-layered perovskite structure. While this is the stable structure for RE=La and Nd, it is metastable for RE=Sm and Gd. The metastable compounds are formed directly through epitaxial stabilization at these high temperatures and are shown to be isostructural to monoclinic La{sub 2}Ti{sub 2}O{sub 7}.more » The a, b, and c lattice parameters decreased monotonically with decreasing size of the RE cation, while the monoclinic angle remained fairly constant. The epitaxial relationship between the (110)-layered RE{sub 2}Ti{sub 2}O{sub 7} films and the SrTiO{sub 3}(110) substrate was found by XRD and transmission electron microscopy to be {l_brace}001{r_brace}<010>{sub film}||{l_brace}110{r_brace}<11-bar0>{sub SrTiO{sub 3}}. The single-phase, metastable, epitaxial, 100 nm thick films maintained the layered perovskite structure even after annealing at 900 deg. C for two hours in 200 Torr of oxygen. - Graphical abstract: Epitaxial thin films of RE{sub 2}Ti{sub 2}O{sub 7} (RE=Gd, Sm, Nd, and La) were deposited on single crystal SrTiO{sub 3} (110) substrates using pulsed laser deposition (PLD). All compositions adopted the monoclinic (110)-layered perovskite structure, which is the stable phase for La{sub 2}Ti{sub 2}O{sub 7} and Nd{sub 2}Ti{sub 2}O{sub 7} but is metastable with respect to the pyrochlore phase for Sm{sub 2}Ti{sub 2}O{sub 7} and Gd{sub 2}Ti{sub 2}O{sub 7}.« less
  • Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals with a tetragonal tungsten bronze (TTB) structure are synthesized using a conventional glass crystallization technique in 2.3RE{sub 2}O{sub 3}-27.4BaO-34.3Nb{sub 2}O{sub 5}-36B{sub 2}O{sub 3} (mol%) (RE=Sm, Eu, Gd, Dy, and Er) glasses. One sharp crystallization peak is observed at {approx}670 Degree-Sign C in both powdered and bulk glasses, and the formation of Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals with unit cell parameters of a{approx}1.24 nm and c{approx}0.39 nm was confirmed. It is found from high resolution transmission electron microscope observations that the morphology of Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals is ellipsoidal. Their average particlemore » size is in the range of 15-60 nm and decreases with decreasing ionic radius of RE{sup 3+} being present in the precursor glasses. The optical transparent crystallized glass (bulk) shows the total photoluminescence (PL) quantum yield of 53% in the visible region of Eu{sup 3+} ions, suggesting a high potential of Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals as PL materials. - Graphical abstract: This figure shows a TEM photograph for the heat-treated (667 Degree-Sign C, 3 h) sample of 2.3Dy{sub 2}O{sub 3}-27.4BaO-34.3Nb{sub 2}O{sub 5}-36B{sub 2}O{sub 3}. An ellipsoidal-shaped Ba{sub 1-x}Dy{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystal with diameters of 17 and 28 nm is observed. The ellipsoidal morphology is a common feature in Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals synthesized by the crystallization of 2.3RE{sub 2}O{sub 3}-27.4BaO-34.3Nb{sub 2}O{sub 5}-36B{sub 2}O{sub 3} glasses. Highlights: Black-Right-Pointing-Pointer Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals with a tetragonal tungsten bronze structure are synthesized. Black-Right-Pointing-Pointer A glass crystallization technique was applied. Black-Right-Pointing-Pointer The morphology of Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals is ellipsoidal. Black-Right-Pointing-Pointer The average particle size with 15-60 nm decreases with decreasing ionic radius of RE{sup 3+}. Black-Right-Pointing-Pointer Ba{sub 1-x}RE{sub 2x/3}Nb{sub 2}O{sub 6} nanocrystals have a high potential as photoluminescence materials.« less
  • A new family of mixed lanthanide(III) and iron(III) oxo-phosphate phases, Rb{sub 7}LnFe{sub 6}O{sub 2}(PO{sub 4}){sub 8} (Ln=Sm 1, Eu 2, Gd 3, Dy 4), was isolated by using a high-temperature, solid-state method in molten-salt media. The X-ray single-crystal structure analysis shows that these isomorphic derivatives crystallize in a triclinic space group P-1 (no. 2); Z=1. The 3-D framework of these 3d-4f oxo-phosphates are comprised of LnO{sub 6} octahedral, FeO{sub 5} trigonal bipyramidal (tbp), and {mu}{sub 3}-oxo [Fe{sub 4}O{sub 18}] tetrameric units interconnected through PO{sub 4} tetrahedra. The preliminary results of the temperature-dependent magnetic susceptibility measurements for selected compounds (1, 3,more » 4) reveal antiferromagnetic-like behavior. 1 shows a weak antiferromagnetric ordering at T{sub N}={approx}7 K while others show little evidence of long-range magnetic order down to 2 K. All three compounds have measured magnetic moments significantly smaller than the expected values. - Graphical abstract: The extended framework is described by the connectivity of three distinct types of paramagnetic units. The temperature-dependent, lower than expected effective magnetic moments are reported. Highlights: Black-Right-Pointing-Pointer A new family of mixed lanthanide(III) and iron(III) oxo-phosphates is isolated. Black-Right-Pointing-Pointer Features PO{sub 4}-linked paramagnetic units of LnO{sub 6}, FeO{sub 5}, and {mu}{sub 3}-oxo [Fe{sub 4}O{sub 18}]. Black-Right-Pointing-Pointer Sm-derivative orders at T{sub N}{approx}7 K while Gd- and Dy-derivatives show absence of order.« less
  • New layered Co oxides of nominal formula Sr{sub 2}(Ln{sub 0.8}Ca{sub 0.2})Co{sub 2}O{sub 6} (Ln = Sm, Eu, Gd, Tb, Dy, Ho, and Y) are reported. Single-phase polycrystalline samples were obtained at compositions Sr{sub 2}Y{sub 1{minus}x}Ca{sub x}Co{sub 2}{sup 2.5+}O{sub 6{minus}{delta}} (0.2 {le} x {le} 0.5; 0 {le} {delta} {le} 0.24), Sr{sub 2}Y{sub 1{minus}x}Ca{sub x}Co{sub 2}{sup 3.4+}O{sub 6+{delta}{prime}} (0.2 {le} x {le} 0.5; 0.62 {le} {delta}{prime} {le} 0.79), and Sr{sub 2}Dy{sub 0.8}Ca{sub 0.2}Co{sub 2}O{sub 6.09}. Powder X-ray and neutron diffraction, thermogravimetric analysis, magnetic susceptibility, and ac resistivity measurements were used to characterize the samples. The tetragonal unit cell for Sr{sub 2}Y{sub 0.8}Ca{submore » 0.2}Co{sub 2}O{sub 6.00} (I4/mmm; a = 3.82765(6) {angstrom}, and c = 19.5795(3) {angstrom}) is comparable to that of the double layer superconducting copper oxide La{sub 2{minus}x}Sr{sub x}CaCu{sub 2}O{sub 6}. A long-range antiferromagnetic (AF) ordered state below about 300 K is found for Sr{sub 2}Y{sub 1{minus}x}Ca{sub x}Co{sub x}{sup 2.5+}O{sub 6{minus}{delta}}, and a magnetically glassy state below about 40 K for the oxidized AF phases. All materials are electrically insulating.« less